ABOVE: Excavations on the Tibetan Plateau have revealed thousands of fragments of Paleolithic tools.
YINGSHUAI JIN
Even a seasoned mystery novelist might find it difficult to come up with a more tantalizing string of clues than those left by the Denisovans. Paleontologists found the only remains of the ancient hominin species in a Siberian cave in 2008. Yet a genetic analysis published early last year reported that, among modern-day human populations studied, the largest proportion of Denisovan-derived genes, about 5 percent, is found a watery hemisphere away—in residents of Oceania, in the South Pacific (Cell, 175:P53–61.E9). Another study found that a distinctive variant of the gene EPAS1 that helps Tibetans cope with high-altitude conditions is similar to an allele found in the Denisovan genome, and likely was acquired many millennia ago through interbreeding with the now-extinct species and spread through the population thanks to natural selection (Nature, 512:194–97, 2014).
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